Nowadays, computers are widely used and become essential parts in our daily lives. In addition to the working purposes, computers may be employed as amusement tools. With increasing development of computers, computer peripheral devices make great progress. The computer peripheral devices comprise various input devices such as keyboard devices, mouse devices or touchpads. Conventionally, the computer peripheral device is in communication with the computer by using a physical connecting wire as a connecting medium. In recent years, the computer peripheral device is in communication with the computer by using a wireless signal as the connecting medium. Since the wireless peripheral device is no longer equipped with the physical connecting wire, the wireless peripheral device can be used and carried more conveniently.
Although the wireless peripheral device without the physical connecting wire has the above benefits, the wireless peripheral device still has some drawbacks. For example, the wired peripheral device can acquire stable electric power from the computer system through the physical connecting wire, but the wireless peripheral device fails to acquire stable electric power from the computer system. For providing stable electric power, the wireless peripheral device has to be additionally equipped with a battery.
Since the electric power stored in the battery may be used up, the user has to frequently pay attention to the battery capacity of the wireless peripheral device. Before the battery capacity is used up, the battery may be replaced with a new one or the battery may be charged by a charger. However, most users may often ignore the battery capacity. Consequently, when the battery capacity is used up, the user may usually find that no available new battery is acquired or no charger is available to charge the battery. Under this circumstance, the wireless peripheral device cannot be used.
For solving the above drawbacks, a wireless induction system and a battery capacity reminding method were disclosed in Taiwanese Patent No. I284273, which was entitled “Cordless electromagnetic induction system and method for reminding battery capacity”. The wireless induction system disclosed in this patent comprises a wireless pen, a graphics tablet and a host. The wireless pen comprises a battery, a radio frequency oscillator and a battery voltage detector. The graphics tablet comprises a radio frequency receiver. When the battery voltage detector detects that the battery capacity of the wireless pen is lower than a specified value, the radio frequency oscillator issues a radio frequency signal to the radio frequency receiver of the graphics tablet. After the radio frequency signal is received, the graphics tablet will notify the host of issuing a low battery warning signal to remind the user. The low battery warning signal is for example a sound signal, a visible signal, a pop-up window, a flickering signal shown on a display screen, or a light color change.
However, the low battery warning signal may only last for a certain time period (e.g. about 3 to 5 seconds). For example, the pop-up window may last for 5 seconds, and then disappear. When the low battery warning signal generates, the user may leave the host without watching or hearing the low battery warning signal. After the user comes back to operate the host, the low battery warning signal has already disappeared. Under this circumstance, the battery capacity reminding function is lost.
Therefore, there is a need of providing a battery capacity displaying system for a wireless peripheral device in order to assure that the user receives the battery capacity message.